Debian gives you a choice though. If you want stability, install the stable release. If you want newer packages, install the testing release. Just be sure to get security updates from unstable (sid) if you do that.
“stable” in this context means that stuff doesn’t change often. It doesn’t mean “stable” as in reliable / never crashes, although Debian is good at that too.
Apparently MacOS apps can be sandboxed and store data securely such that no other apps can access it, in an encrypted format. I wasn’t aware of this either, but it’s been a while since I’ve used MacOS. It sounds like the ChatGPT app explicitly opted out from this sandboxing model.